Root/block/blk-sysfs.c

1/*
2 * Functions related to sysfs handling
3 */
4#include <linux/kernel.h>
5#include <linux/slab.h>
6#include <linux/module.h>
7#include <linux/bio.h>
8#include <linux/blkdev.h>
9#include <linux/blktrace_api.h>
10
11#include "blk.h"
12#include "blk-cgroup.h"
13
14struct queue_sysfs_entry {
15    struct attribute attr;
16    ssize_t (*show)(struct request_queue *, char *);
17    ssize_t (*store)(struct request_queue *, const char *, size_t);
18};
19
20static ssize_t
21queue_var_show(unsigned long var, char *page)
22{
23    return sprintf(page, "%lu\n", var);
24}
25
26static ssize_t
27queue_var_store(unsigned long *var, const char *page, size_t count)
28{
29    int err;
30    unsigned long v;
31
32    err = strict_strtoul(page, 10, &v);
33    if (err || v > UINT_MAX)
34        return -EINVAL;
35
36    *var = v;
37
38    return count;
39}
40
41static ssize_t queue_requests_show(struct request_queue *q, char *page)
42{
43    return queue_var_show(q->nr_requests, (page));
44}
45
46static ssize_t
47queue_requests_store(struct request_queue *q, const char *page, size_t count)
48{
49    struct request_list *rl;
50    unsigned long nr;
51    int ret;
52
53    if (!q->request_fn)
54        return -EINVAL;
55
56    ret = queue_var_store(&nr, page, count);
57    if (ret < 0)
58        return ret;
59
60    if (nr < BLKDEV_MIN_RQ)
61        nr = BLKDEV_MIN_RQ;
62
63    spin_lock_irq(q->queue_lock);
64    q->nr_requests = nr;
65    blk_queue_congestion_threshold(q);
66
67    /* congestion isn't cgroup aware and follows root blkcg for now */
68    rl = &q->root_rl;
69
70    if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
71        blk_set_queue_congested(q, BLK_RW_SYNC);
72    else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
73        blk_clear_queue_congested(q, BLK_RW_SYNC);
74
75    if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
76        blk_set_queue_congested(q, BLK_RW_ASYNC);
77    else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
78        blk_clear_queue_congested(q, BLK_RW_ASYNC);
79
80    blk_queue_for_each_rl(rl, q) {
81        if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
82            blk_set_rl_full(rl, BLK_RW_SYNC);
83        } else {
84            blk_clear_rl_full(rl, BLK_RW_SYNC);
85            wake_up(&rl->wait[BLK_RW_SYNC]);
86        }
87
88        if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
89            blk_set_rl_full(rl, BLK_RW_ASYNC);
90        } else {
91            blk_clear_rl_full(rl, BLK_RW_ASYNC);
92            wake_up(&rl->wait[BLK_RW_ASYNC]);
93        }
94    }
95
96    spin_unlock_irq(q->queue_lock);
97    return ret;
98}
99
100static ssize_t queue_ra_show(struct request_queue *q, char *page)
101{
102    unsigned long ra_kb = q->backing_dev_info.ra_pages <<
103                    (PAGE_CACHE_SHIFT - 10);
104
105    return queue_var_show(ra_kb, (page));
106}
107
108static ssize_t
109queue_ra_store(struct request_queue *q, const char *page, size_t count)
110{
111    unsigned long ra_kb;
112    ssize_t ret = queue_var_store(&ra_kb, page, count);
113
114    if (ret < 0)
115        return ret;
116
117    q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
118
119    return ret;
120}
121
122static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
123{
124    int max_sectors_kb = queue_max_sectors(q) >> 1;
125
126    return queue_var_show(max_sectors_kb, (page));
127}
128
129static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
130{
131    return queue_var_show(queue_max_segments(q), (page));
132}
133
134static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
135{
136    return queue_var_show(q->limits.max_integrity_segments, (page));
137}
138
139static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
140{
141    if (blk_queue_cluster(q))
142        return queue_var_show(queue_max_segment_size(q), (page));
143
144    return queue_var_show(PAGE_CACHE_SIZE, (page));
145}
146
147static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
148{
149    return queue_var_show(queue_logical_block_size(q), page);
150}
151
152static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
153{
154    return queue_var_show(queue_physical_block_size(q), page);
155}
156
157static ssize_t queue_io_min_show(struct request_queue *q, char *page)
158{
159    return queue_var_show(queue_io_min(q), page);
160}
161
162static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
163{
164    return queue_var_show(queue_io_opt(q), page);
165}
166
167static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
168{
169    return queue_var_show(q->limits.discard_granularity, page);
170}
171
172static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
173{
174    return sprintf(page, "%llu\n",
175               (unsigned long long)q->limits.max_discard_sectors << 9);
176}
177
178static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
179{
180    return queue_var_show(queue_discard_zeroes_data(q), page);
181}
182
183static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
184{
185    return sprintf(page, "%llu\n",
186        (unsigned long long)q->limits.max_write_same_sectors << 9);
187}
188
189
190static ssize_t
191queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
192{
193    unsigned long max_sectors_kb,
194        max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
195            page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
196    ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
197
198    if (ret < 0)
199        return ret;
200
201    if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
202        return -EINVAL;
203
204    spin_lock_irq(q->queue_lock);
205    q->limits.max_sectors = max_sectors_kb << 1;
206    spin_unlock_irq(q->queue_lock);
207
208    return ret;
209}
210
211static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
212{
213    int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
214
215    return queue_var_show(max_hw_sectors_kb, (page));
216}
217
218#define QUEUE_SYSFS_BIT_FNS(name, flag, neg) \
219static ssize_t \
220queue_show_##name(struct request_queue *q, char *page) \
221{ \
222    int bit; \
223    bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags); \
224    return queue_var_show(neg ? !bit : bit, page); \
225} \
226static ssize_t \
227queue_store_##name(struct request_queue *q, const char *page, size_t count) \
228{ \
229    unsigned long val; \
230    ssize_t ret; \
231    ret = queue_var_store(&val, page, count); \
232    if (ret < 0) \
233         return ret; \
234    if (neg) \
235        val = !val; \
236                                    \
237    spin_lock_irq(q->queue_lock); \
238    if (val) \
239        queue_flag_set(QUEUE_FLAG_##flag, q); \
240    else \
241        queue_flag_clear(QUEUE_FLAG_##flag, q); \
242    spin_unlock_irq(q->queue_lock); \
243    return ret; \
244}
245
246QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
247QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
248QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
249#undef QUEUE_SYSFS_BIT_FNS
250
251static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
252{
253    return queue_var_show((blk_queue_nomerges(q) << 1) |
254                   blk_queue_noxmerges(q), page);
255}
256
257static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
258                    size_t count)
259{
260    unsigned long nm;
261    ssize_t ret = queue_var_store(&nm, page, count);
262
263    if (ret < 0)
264        return ret;
265
266    spin_lock_irq(q->queue_lock);
267    queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
268    queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
269    if (nm == 2)
270        queue_flag_set(QUEUE_FLAG_NOMERGES, q);
271    else if (nm)
272        queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
273    spin_unlock_irq(q->queue_lock);
274
275    return ret;
276}
277
278static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
279{
280    bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
281    bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
282
283    return queue_var_show(set << force, page);
284}
285
286static ssize_t
287queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
288{
289    ssize_t ret = -EINVAL;
290#if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
291    unsigned long val;
292
293    ret = queue_var_store(&val, page, count);
294    if (ret < 0)
295        return ret;
296
297    spin_lock_irq(q->queue_lock);
298    if (val == 2) {
299        queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
300        queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
301    } else if (val == 1) {
302        queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
303        queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
304    } else if (val == 0) {
305        queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
306        queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
307    }
308    spin_unlock_irq(q->queue_lock);
309#endif
310    return ret;
311}
312
313static struct queue_sysfs_entry queue_requests_entry = {
314    .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
315    .show = queue_requests_show,
316    .store = queue_requests_store,
317};
318
319static struct queue_sysfs_entry queue_ra_entry = {
320    .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
321    .show = queue_ra_show,
322    .store = queue_ra_store,
323};
324
325static struct queue_sysfs_entry queue_max_sectors_entry = {
326    .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
327    .show = queue_max_sectors_show,
328    .store = queue_max_sectors_store,
329};
330
331static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
332    .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
333    .show = queue_max_hw_sectors_show,
334};
335
336static struct queue_sysfs_entry queue_max_segments_entry = {
337    .attr = {.name = "max_segments", .mode = S_IRUGO },
338    .show = queue_max_segments_show,
339};
340
341static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
342    .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
343    .show = queue_max_integrity_segments_show,
344};
345
346static struct queue_sysfs_entry queue_max_segment_size_entry = {
347    .attr = {.name = "max_segment_size", .mode = S_IRUGO },
348    .show = queue_max_segment_size_show,
349};
350
351static struct queue_sysfs_entry queue_iosched_entry = {
352    .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
353    .show = elv_iosched_show,
354    .store = elv_iosched_store,
355};
356
357static struct queue_sysfs_entry queue_hw_sector_size_entry = {
358    .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
359    .show = queue_logical_block_size_show,
360};
361
362static struct queue_sysfs_entry queue_logical_block_size_entry = {
363    .attr = {.name = "logical_block_size", .mode = S_IRUGO },
364    .show = queue_logical_block_size_show,
365};
366
367static struct queue_sysfs_entry queue_physical_block_size_entry = {
368    .attr = {.name = "physical_block_size", .mode = S_IRUGO },
369    .show = queue_physical_block_size_show,
370};
371
372static struct queue_sysfs_entry queue_io_min_entry = {
373    .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
374    .show = queue_io_min_show,
375};
376
377static struct queue_sysfs_entry queue_io_opt_entry = {
378    .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
379    .show = queue_io_opt_show,
380};
381
382static struct queue_sysfs_entry queue_discard_granularity_entry = {
383    .attr = {.name = "discard_granularity", .mode = S_IRUGO },
384    .show = queue_discard_granularity_show,
385};
386
387static struct queue_sysfs_entry queue_discard_max_entry = {
388    .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
389    .show = queue_discard_max_show,
390};
391
392static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
393    .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
394    .show = queue_discard_zeroes_data_show,
395};
396
397static struct queue_sysfs_entry queue_write_same_max_entry = {
398    .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
399    .show = queue_write_same_max_show,
400};
401
402static struct queue_sysfs_entry queue_nonrot_entry = {
403    .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
404    .show = queue_show_nonrot,
405    .store = queue_store_nonrot,
406};
407
408static struct queue_sysfs_entry queue_nomerges_entry = {
409    .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
410    .show = queue_nomerges_show,
411    .store = queue_nomerges_store,
412};
413
414static struct queue_sysfs_entry queue_rq_affinity_entry = {
415    .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
416    .show = queue_rq_affinity_show,
417    .store = queue_rq_affinity_store,
418};
419
420static struct queue_sysfs_entry queue_iostats_entry = {
421    .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
422    .show = queue_show_iostats,
423    .store = queue_store_iostats,
424};
425
426static struct queue_sysfs_entry queue_random_entry = {
427    .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
428    .show = queue_show_random,
429    .store = queue_store_random,
430};
431
432static struct attribute *default_attrs[] = {
433    &queue_requests_entry.attr,
434    &queue_ra_entry.attr,
435    &queue_max_hw_sectors_entry.attr,
436    &queue_max_sectors_entry.attr,
437    &queue_max_segments_entry.attr,
438    &queue_max_integrity_segments_entry.attr,
439    &queue_max_segment_size_entry.attr,
440    &queue_iosched_entry.attr,
441    &queue_hw_sector_size_entry.attr,
442    &queue_logical_block_size_entry.attr,
443    &queue_physical_block_size_entry.attr,
444    &queue_io_min_entry.attr,
445    &queue_io_opt_entry.attr,
446    &queue_discard_granularity_entry.attr,
447    &queue_discard_max_entry.attr,
448    &queue_discard_zeroes_data_entry.attr,
449    &queue_write_same_max_entry.attr,
450    &queue_nonrot_entry.attr,
451    &queue_nomerges_entry.attr,
452    &queue_rq_affinity_entry.attr,
453    &queue_iostats_entry.attr,
454    &queue_random_entry.attr,
455    NULL,
456};
457
458#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
459
460static ssize_t
461queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
462{
463    struct queue_sysfs_entry *entry = to_queue(attr);
464    struct request_queue *q =
465        container_of(kobj, struct request_queue, kobj);
466    ssize_t res;
467
468    if (!entry->show)
469        return -EIO;
470    mutex_lock(&q->sysfs_lock);
471    if (blk_queue_dying(q)) {
472        mutex_unlock(&q->sysfs_lock);
473        return -ENOENT;
474    }
475    res = entry->show(q, page);
476    mutex_unlock(&q->sysfs_lock);
477    return res;
478}
479
480static ssize_t
481queue_attr_store(struct kobject *kobj, struct attribute *attr,
482            const char *page, size_t length)
483{
484    struct queue_sysfs_entry *entry = to_queue(attr);
485    struct request_queue *q;
486    ssize_t res;
487
488    if (!entry->store)
489        return -EIO;
490
491    q = container_of(kobj, struct request_queue, kobj);
492    mutex_lock(&q->sysfs_lock);
493    if (blk_queue_dying(q)) {
494        mutex_unlock(&q->sysfs_lock);
495        return -ENOENT;
496    }
497    res = entry->store(q, page, length);
498    mutex_unlock(&q->sysfs_lock);
499    return res;
500}
501
502static void blk_free_queue_rcu(struct rcu_head *rcu_head)
503{
504    struct request_queue *q = container_of(rcu_head, struct request_queue,
505                           rcu_head);
506    kmem_cache_free(blk_requestq_cachep, q);
507}
508
509/**
510 * blk_release_queue: - release a &struct request_queue when it is no longer needed
511 * @kobj: the kobj belonging to the request queue to be released
512 *
513 * Description:
514 * blk_release_queue is the pair to blk_init_queue() or
515 * blk_queue_make_request(). It should be called when a request queue is
516 * being released; typically when a block device is being de-registered.
517 * Currently, its primary task it to free all the &struct request
518 * structures that were allocated to the queue and the queue itself.
519 *
520 * Caveat:
521 * Hopefully the low level driver will have finished any
522 * outstanding requests first...
523 **/
524static void blk_release_queue(struct kobject *kobj)
525{
526    struct request_queue *q =
527        container_of(kobj, struct request_queue, kobj);
528
529    blk_sync_queue(q);
530
531    blkcg_exit_queue(q);
532
533    if (q->elevator) {
534        spin_lock_irq(q->queue_lock);
535        ioc_clear_queue(q);
536        spin_unlock_irq(q->queue_lock);
537        elevator_exit(q->elevator);
538    }
539
540    blk_exit_rl(&q->root_rl);
541
542    if (q->queue_tags)
543        __blk_queue_free_tags(q);
544
545    blk_trace_shutdown(q);
546
547    bdi_destroy(&q->backing_dev_info);
548
549    ida_simple_remove(&blk_queue_ida, q->id);
550    call_rcu(&q->rcu_head, blk_free_queue_rcu);
551}
552
553static const struct sysfs_ops queue_sysfs_ops = {
554    .show = queue_attr_show,
555    .store = queue_attr_store,
556};
557
558struct kobj_type blk_queue_ktype = {
559    .sysfs_ops = &queue_sysfs_ops,
560    .default_attrs = default_attrs,
561    .release = blk_release_queue,
562};
563
564int blk_register_queue(struct gendisk *disk)
565{
566    int ret;
567    struct device *dev = disk_to_dev(disk);
568    struct request_queue *q = disk->queue;
569
570    if (WARN_ON(!q))
571        return -ENXIO;
572
573    /*
574     * Initialization must be complete by now. Finish the initial
575     * bypass from queue allocation.
576     */
577    blk_queue_bypass_end(q);
578
579    ret = blk_trace_init_sysfs(dev);
580    if (ret)
581        return ret;
582
583    ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
584    if (ret < 0) {
585        blk_trace_remove_sysfs(dev);
586        return ret;
587    }
588
589    kobject_uevent(&q->kobj, KOBJ_ADD);
590
591    if (!q->request_fn)
592        return 0;
593
594    ret = elv_register_queue(q);
595    if (ret) {
596        kobject_uevent(&q->kobj, KOBJ_REMOVE);
597        kobject_del(&q->kobj);
598        blk_trace_remove_sysfs(dev);
599        kobject_put(&dev->kobj);
600        return ret;
601    }
602
603    return 0;
604}
605
606void blk_unregister_queue(struct gendisk *disk)
607{
608    struct request_queue *q = disk->queue;
609
610    if (WARN_ON(!q))
611        return;
612
613    if (q->request_fn)
614        elv_unregister_queue(q);
615
616    kobject_uevent(&q->kobj, KOBJ_REMOVE);
617    kobject_del(&q->kobj);
618    blk_trace_remove_sysfs(disk_to_dev(disk));
619    kobject_put(&disk_to_dev(disk)->kobj);
620}
621

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